freeCodeCamp/curriculum/challenges/chinese/07-scientific-computing-with-python/scientific-computing-with-python-projects/arithmetic-formatter.md

id, title, challengeType, forumTopicId, dashedName

id	title	challengeType	forumTopicId	dashedName
5e44412c903586ffb414c94c	算术格式化	23	462359	arithmetic-formatter

--description--

小学生经常把算术题垂直排列，这样更容易解决。 例如，“235 + 52” 变成：

  235
+  52
-----

Finish the arithmetic_arranger function that receives a list of strings which are arithmetic problems, and returns the problems arranged vertically and side-by-side. 该函数应该接受可选的第二个参数。 当第二个参数设置为 True 时，应显示答案。

示例

函数调用：

arithmetic_arranger(["32 + 698", "3801 - 2", "45 + 43", "123 + 49"])

输出:

   32      3801      45      123
+ 698    -    2    + 43    +  49
-----    ------    ----    -----

函数调用：

arithmetic_arranger(["32 + 8", "1 - 3801", "9999 + 9999", "523 - 49"], True)

输出:

  32         1      9999      523
+  8    - 3801    + 9999    -  49
----    ------    ------    -----
  40     -3800     19998      474

规则

如果提供的问题格式正确，该函数将返回正确的转换，否则，它将 返回 一个 字符串 来描述对用户有意义的错误。

• 会返回错误的情况：
  • 如果提供给函数的问题过多。 The limit is five, anything more will return: 'Error: Too many problems.'
  • 函数可以接受的运算符是加法和减法。 乘法和除法将返回错误。 本要点中未提及的其他运算符将不需要进行测试。 The error returned will be: "Error: Operator must be '+' or '-'."
  • 每个数字（操作数）应该只包含数字。 Otherwise, the function will return: 'Error: Numbers must only contain digits.'
  • 每个操作数（即运算符每一侧的数字）的宽度最多为四位数字。 Otherwise, the error string returned will be: 'Error: Numbers cannot be more than four digits.'
• 如果用户提供了正确格式的问题，返回的转换将遵循以下规则：
  • 操作符和两个操作数中最长的一个之间应该有一个空格，操作符将与第二个操作数在同一行，两个操作数的顺序与提供的相同（第一个是上面的，第二个是下面的）。
  • 数字应该右对齐。
  • 每个问题之间应该有四个空格。
  • 每个问题的底部都应该有破折号。 破折号应该单独沿着每个问题的整个长度延伸。 （上面的例子展示了这应该是什么样子。）

--hints--

arithmetic_arranger(["3801 - 2", "123 + 49"]) should return 3801 123\n- 2 + 49\n------ -----.

({
  test: () => {
    runPython(`
from unittest import TestCase

TestCase().assertEqual(arithmetic_arranger(["3801 - 2", "123 + 49"]), '  3801      123\\n-    2    +  49\\n------    -----')`);
  }
})

arithmetic_arranger(["1 + 2", "1 - 9380"]) should return 1 1\n+ 2 - 9380\n--- ------.

({
  test: () => {
    runPython(`
from unittest import TestCase

TestCase().assertEqual(arithmetic_arranger(["1 + 2", "1 - 9380"]), '  1         1\\n+ 2    - 9380\\n---    ------')`);
  }
})

arithmetic_arranger(["3 + 855", "3801 - 2", "45 + 43", "123 + 49"]) should return 3 3801 45 123\n+ 855 - 2 + 43 + 49\n----- ------ ---- -----.

({
  test: () => {
    runPython(`
from unittest import TestCase

TestCase().assertEqual(arithmetic_arranger(["3 + 855", "3801 - 2", "45 + 43", "123 + 49"]), '    3      3801      45      123\\n+ 855    -    2    + 43    +  49\\n-----    ------    ----    -----')`);
  }
})

arithmetic_arranger(["11 + 4", "3801 - 2999", "1 + 2", "123 + 49", "1 - 9380"]) should return 11 3801 1 123 1\n+ 4 - 2999 + 2 + 49 - 9380\n---- ------ --- ----- ------.

({
  test: () => {
    runPython(`
from unittest import TestCase

TestCase().assertEqual(arithmetic_arranger(["11 + 4", "3801 - 2999", "1 + 2", "123 + 49", "1 - 9380"]), '  11      3801      1      123         1\\n+  4    - 2999    + 2    +  49    - 9380\\n----    ------    ---    -----    ------')`);
  }
})

arithmetic_arranger(["44 + 815", "909 - 2", "45 + 43", "123 + 49", "888 + 40", "653 + 87"]) should return 'Error: Too many problems.'.

({
  test: () => {
    runPython(`
from unittest import TestCase

TestCase().assertEqual(arithmetic_arranger(["44 + 815", "909 - 2", "45 + 43", "123 + 49", "888 + 40", "653 + 87"]), 'Error: Too many problems.')`);
  }
})

arithmetic_arranger(["3 / 855", "3801 - 2", "45 + 43", "123 + 49"]) should return "Error: Operator must be '+' or '-'.".

({
  test: () => {
    runPython(`
from unittest import TestCase

TestCase().assertEqual(arithmetic_arranger(["3 / 855", "3801 - 2", "45 + 43", "123 + 49"]), "Error: Operator must be '+' or '-'.")`);
  }
})

arithmetic_arranger(["24 + 85215", "3801 - 2", "45 + 43", "123 + 49"]) should return 'Error: Numbers cannot be more than four digits.'.

({
  test: () => {
    runPython(`
from unittest import TestCase

TestCase().assertEqual(arithmetic_arranger(["24 + 85215", "3801 - 2", "45 + 43", "123 + 49"]), "Error: Numbers cannot be more than four digits.")`);
  }
})

arithmetic_arranger(["98 + 3g5", "3801 - 2", "45 + 43", "123 + 49"]) should return 'Error: Numbers must only contain digits.'.

({
  test: () => {
    runPython(`
from unittest import TestCase

TestCase().assertEqual(arithmetic_arranger(["98 + 3g5", "3801 - 2", "45 + 43", "123 + 49"]), "Error: Numbers must only contain digits.")`);
  }
})

arithmetic_arranger(["3 + 855", "988 + 40"], True) should return 3 988\n+ 855 + 40\n----- -----\n 858 1028.

({
  test: () => {
    runPython(`
from unittest import TestCase

TestCase().assertEqual(arithmetic_arranger(["3 + 855", "988 + 40"], True), "    3      988\\n+ 855    +  40\\n-----    -----\\n  858     1028")`);
  }
})

arithmetic_arranger(["32 - 698", "1 - 3801", "45 + 43", "123 + 49", "988 + 40"], True) should return 32 1 45 123 988\n- 698 - 3801 + 43 + 49 + 40\n----- ------ ---- ----- -----\n -666 -3800 88 172 1028.

({
  test: () => {
    runPython(`
from unittest import TestCase

TestCase().assertEqual(arithmetic_arranger(["32 - 698", "1 - 3801", "45 + 43", "123 + 49", "988 + 40"], True), "   32         1      45      123      988\\n- 698    - 3801    + 43    +  49    +  40\\n-----    ------    ----    -----    -----\\n -666     -3800      88      172     1028")`);
  }
})

--seed--

--seed-contents--

def arithmetic_arranger(problems, show_answers=False):

    return problems

print(f'\n{arithmetic_arranger(["32 + 698", "3801 - 2", "45 + 43", "123 + 49"])}')

--solutions--

def arithmetic_arranger(problems, result=False):

    lin1 = ""
    lin2 = ""
    lin3 = ""
    lin4 = ""

    if len(problems) > 5:
        return 'Error: Too many problems.'
    for problem in problems:
        [num1, sym, num2] = problem.split()
        sign = ['+', '-']
        if sym not in sign:
            return ("Error: Operator must be '+' or '-'.")
        if len(num1) > 4 or len(num2) > 4:
            return ("Error: Numbers cannot be more than four digits.")
        if not num1.isnumeric() or not num2.isnumeric():
            return ("Error: Numbers must only contain digits.")

        lin1 += "  " + num1 + "    " if len(num1) >= len(
            num2) else " " * (len(num2) + 2 - len(num1)) + num1 + "    "
        lin2 += sym + " " + num2 + "    " if len(num2) >= len(
            num1) else sym + " " * (len(num1) - len(num2) + 1) + num2 + "    "
        nmax = (len(num1) + 2) if len(num1) >= len(num2) else (len(num2) + 2)
        lin3 += "-" * nmax + "    "
        op = int(num1) + int(num2) if sym == "+" else int(num1) - int(num2)
        lin4 += (" " * (nmax - len(str(op)))) + str(op) + "    "

    arranged_problems = lin1.rstrip() + "\n" + lin2.rstrip(
    ) + "\n" + lin3.rstrip()
    if result:
        arranged_problems += "\n" + lin4.rstrip()

    return arranged_problems